1. Field of the Invention
The present invention generally relates to an antenna for radiating an electromagnetic field from at least one radiating surface of a dielectric layer to achieve a desired polarization radiation.
2. Description of the Related Art
Various antennas for receiving circularly and/or linearly polarized RF signals are known in the art. In the antennas of the prior art, dielectric layers are typically used to isolate a radiation element, such as a discrete metal-based patch radiation element, from other elements of the antenna, such as a feeding probe and a ground plane. One example of such an antenna is disclosed in United States Patent Application Publication No. 2005/0195114 to Yegin et al. (the Yegin et al. publication). The Yegin et al. publication discloses an antenna mounted to a windshield of an automobile. The antenna includes a ground plane supporting dielectric layer. Further, the dielectric layer is supporting a metal layer having a slot, and the feeding probe excites the metal layer to radiate across the edges of the dielectric layer.
Although the antennas of the prior art can receive and/or transmit circularly and/or linearly polarized RF signals, there remains an opportunity to provide an antenna that maintains the ability to achieve circular and/or linear polarization radiation from all surfaces of the dielectric layer that extend transverse relative to the ground plane and are parallel to and spaced from the ground plane and maintain or improve the performance of the antenna, including increasing bandwidth, increasing efficiency, decreasing size and decreasing manufacturing complexity. Therefore, an antenna is needed that provides many desired characteristics that increase antenna performance when compared to the antennas of the prior art. In addition, an antenna is needed that may be used as a wideband antenna for multiple applications, including achieving any desired polarization radiation, such as providing both circular polarization and linear polarization. An antenna is needed that also has beam-tilting capabilities. Finally, an antenna is needed that is less sensitive and easier to tune when compared to the antennas of the prior art.